The present invention relates to a device to control the dynamic stability of an industrial vehicle. More specifically, the device according to the present invention is appropriate to be fitted on an industrial vehicle such as lift trucks with telescoping boom, bucket loaders or back-hoe loaders, crane trucks, tractors and similar.
As is known, during operations to manoeuvre or work with these industrial vehicles, the casing or chassis of the vehicle is subjected to a plurality of external loads which can be schematised as forces and moments of forces that tend to influence the stability of the vehicle.
This is accentuated by these phenomena occurring with the vehicle fully loaded and/or on uneven ground. In fact, during operations to manoeuvre an industrial vehicle with suspensions, the entire casing or chassis of the vehicle is subjected to various stresses determined by a series of forces and overturning moments that are produced both due to movement of the load or due to variations in the stability of the vehicle in motion on the ground, all of which may occur in static, almost-static or dynamic conditions.
Measurement of external physical sizes is useful to determine the conditions of operation and stability of the vehicle; for example, it is possible to measure the vertical forces and overturning moments in the various directions of the space to calculate the stability of industrial vehicles with axles with suspensions, during the various manoeuvres of turning, braking, acceleration or lifting the load, in order to calculate the induced forces and the moments of destabilisation of the vehicle.
Currently, the operation to measure these forces and moments can be performed using specifically designed measurement instruments, only by simulation to be performed in the laboratory.
Moreover, to date, the various physical sizes of interest are measured approximately and placed in relation to one another by means of force transducers, which are fixed only externally to the casing of the axle or the chassis of the vehicle, thus influenced by all possible effects of disturbance or drift of the signal to be measured, which can be influenced by the effects of temperature, deflections of the structural components of the axle, operating pressures of the brakes, making the final information inaccurate and unreliable.
Therefore, fitting these transducers in specific positions of each rotating axle does not permit accurate measurements, as they are influenced by many external factors, in addition to those intrinsic to the geometry of the axle or the coupling of the axle with the vehicle chassis.
Lastly, all this requires the development of complex transformation algorithms, appropriate to translate the position through time of each vehicle axle into the fixed coordinates system of the vehicle.
The object of the present invention is, therefore, to produce a device for controlling the dynamic stability of an industrial vehicle which operates in an active and integrated mode in the vehicle, during its normal use, to guarantee the best conditions of stability and self-levelling of this vehicle.
Another object of the present invention is to produce a device for control of the dynamic stability of an industrial vehicle, which can be installed simply and which may allow an operator sitting in the cab to be informed of all conditions in the vicinity of the limit of stability in which the vehicle finds itself operating.
Yet another object of the present invention is to present a device for control of the dynamic stability of an industrial vehicle which considerably increases the reliability and overall comfort of the vehicle to which it is fitted, reducing stresses to which the chassis of the vehicle might be subjected.
These and other objects are attained by a device that controls the dynamic stability of an industrial vehicle, where the chassis of said vehicle is fitted with at least one pair of axles (10xe2x80x2, 10xe2x80x3), extending from each of which are booms (12, 13, 12xe2x80x2, 13xe2x80x2) fitted to the ends of which are articulated steering pivots (14, 15, 14xe2x80x2, 15xe2x80x2) of the wheels of said vehicle, and where interposed between the axle (11) and the chassis (16) of said industrial vehicle are hydraulic cylinders (17, 17xe2x80x2, 18, 18xe2x80x2), wherein each of said hydraulic cylinders (17, 17xe2x80x2, 18, 18xe2x80x2), is associated with pressure transducers (31-34) capable of indicating the loads weighing instantaneously on each wheel hub, using said weight information from said pressure transducers (31-34) in data processing, recognition of the condition of stability of said vehicle, said pressure transducers (31-34) being associated with said hydraulic cylinders (17, 17xe2x80x2, 18, 18xe2x80x2) so as to detect and provide the control unit, as said information is received, (39) with input data on which to base assessment of the stability of said vehicle.
Further characteristics of the present invention are also defined in the subsequent claims.